note Hofmator <p>Ok, first to get the terminology straight, 'node' eq 'vertex' and 'edge' eq 'link'. <p>In your code both nodes and links have an id. Let's look at your original code: <code># this marks the current vertex $explored->{$node->{_id}}++; foreach my $link (@{$node->{_outlinks}}) { # $link isa Link, so $link->{_id} is the id of the link, # not of the vertex!! $do_search->($link->{_to}) unless ($explored->{$link->{_id}}); } </code> Yes, your algorithm is fine, it's just the implementation that has a little bug in it. Here's my (correct) code again, this time written explicitly: <code>$explored->{$node->{_id}}++; foreach my $link (@{$node->{_outlinks}}) { my $new_node = $link->{_to}; $do_search->($new_node) unless ($explored->{$new_node->{_id}}); } </code> <div class="pmsig"><div class="pmsig-85506"> <P>-- Hofmator</P> </div></div> 319780 320105